This invention relates to testing or reconditioning of gas cylinders. More specifically, the invention relates to a process and apparatus for testing the gas cylinders for structural integrity prior to reconditioning of the cylinders.
Industrial gases such as nitrogen, oxygen, and helium are typically supplied in metal cylinders which are refilled many times. Department of Transportation regulations require that each gas cylinder must have a record of successful testing for structural integrity to be refilled using normal procedures. Approved cylinder test methods include hydrostatic testing and ultrasonic testing. Hydrostatic testing typically includes measurement of permanent expansion and elastic expansion. Cylinders which fail a visual inspection, exceed an acceptable permanent expansion, or have unacceptable defects must not be refilled. Cylinders which are acceptable except for inadequate elastic expansion can be used only at a reduced pressure which is typically the pressure limit stamped on the cylinder.
Reconditioning of empty gas cylinders generally involves removing the cylinder valve, inspecting and testing the cylinder, cleaning, drying, and repainting the cylinder, and replacing a cylinder valve on the reconditioned cylinder. Inspection and testing of gas cylinders is usually the bottleneck in the reconditioning process since test conditions and results are determined and documented for each cylinder.
Hydrostatic testing of the gas cylinders was improved by a computerized hydrostatic test station marketed by Galiso, Inc. However, the hydrostatic test stations place much responsibility on a single operator and essentially causes the operator to be the bottleneck in a process that is primarily constrained by the ability of the operator to enter data.
It is an object of the present invention to significantly increase the number of gas cylinders which can be tested for structural integrity by enhancing data entry. Successful debottlenecking of the cylinder testing process will further debottleneck reconditioning of used gas cylinders.